JPH0361029A - Preparation of interior material for car - Google Patents

Abstract

PURPOSE:To obtain lightweight properties and good rigidity and to perform cold press molding by scattering a thermoplastic resin powder containing a foaming agent on an inorg. fiber to form a mat-like article and heating this mat-like article to melt and foam the powder to form a foamed sheet. CONSTITUTION:A thermoplastic resin powder 2 containing a foaming agent is scattered on an inorg. fiber 1 to form a mat-like article 3 which is, in turn, heated from both surfaces thereof by heating apparatuses 4. The thermoplastic resin scattered on the inorg. fiber 1 is melted to become a substitute of a binder to partially bond the inorg. fiber 1. When the mat-like article 3 is further heated to reach the decomposition temp. of the foaming agent, the foaming agent is foamed. By this method, the inorg. fiber 1 bonded to the molten resin of the thermoplastic resin expands in the thickness direction to form a foamed sheet 5 having uniform rigidity. Foaming magnification is pref. 2-10 times. Subsequently, the obtained foamed sheet 5 is subjected to compression molding by a cold press mold 6.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an interior material with excellent thermoformability, and particularly to a method for manufacturing an interior material for an automobile that is suitably used as a ceiling material for an automobile.

[Conventional technology] Automobile ceiling materials are lightweight, rigid, heat resistant, sound absorbing,
Materials with excellent properties such as heat formability are required.

Examples of this type of material include glass fiber mats made by hardening glass fibers with a binder such as thermosetting resin such as phenol, and materials in which inorganic fibers such as glass fibers are mixed with thermoplastic resin fibers such as polyethylene. .

Glass fiber mats have the advantages of being lightweight, providing good sound absorption, and having excellent heat insulation and dimensional stability.

In addition, inorganic fibers mixed with thermoplastic resin fibers,
It had the advantages of being lightweight and bulky, having excellent thermal formability, heat insulation properties, and mechanical strength.

[Problems to be Solved by the Invention] However, although glass fiber mats have the above-mentioned advantages, they are relatively brittle and break or crack during product handling or assembly, making them insufficient as interior materials for automobiles. Rigidity could not be obtained. In order to obtain sufficient rigidity, it was necessary to increase the weight, which required the use of a large amount of material, which increased costs and went against efforts to reduce weight. In order to solve the above problems, a glass fiber mantle reinforced with a foamed phenolic resin layer was proposed. Although the weight of this product can be relatively reduced, since the phenol resin is foamed and cured, the molding takt time becomes long and productivity is poor. In addition, thermosetting resins such as phenol have a high curing temperature and must be molded using heat, resulting in high mold and equipment costs.

On the other hand, inorganic fibers mixed with thermoplastic resin fibers are
Although it has the advantage of being able to be formed by cold pressing, it is necessary to increase the weight of the interior material in order to obtain sufficient rigidity, which runs counter to the recent efforts to reduce the weight of interior materials.

The present invention overcomes the above problems and provides a method for producing an automobile interior material that is lightweight, has good rigidity as an automobile interior material, can be cold press-formed, and can be suitably used as an automobile ceiling material. With the goal.

[Means for Solving the Problems] The means of the present invention for solving the problems is to form a mat-like material by spraying thermoplastic resin powder containing a foaming agent on inorganic fibers, and An interior material for an automobile was manufactured by heating a pine I-shaped material to melt and foam the thermoplastic outer resin powder to form a foamed sheet, and molding the foamed sheet into a desired shape by cold pressing.

[Function] According to the present invention, the thermoplastic resin powder is melted by heating the cloak-like material obtained by spraying the thermoplastic resin powder containing a blowing agent on the inorganic KM II,
Inorganic fibers and thermoplastic resin powder are partially bonded firmly.

Further, by foaming the thermoplastic resin powder, the inorganic fibers spread in the thickness direction of the foamed sheet and are uniformly reinforced.

Furthermore, since the foam sheet is molded into the desired shape by cold pressing, it is possible to bond it to the skin material at the same time as molding, simplifying the process, and improving productivity by folding the sheet.
Since no aspiration is required, mold costs, equipment costs, etc. can be reduced.

〔Example〕

An embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view of a mat-like material 3 obtained by spraying thermoplastic resin powder 2 containing a foaming agent onto inorganic fibers 1.

As the inorganic fibers 1, glass fibers, rock wool, ceramic fibers, carbon fibers, etc. are used. In particular, glass fibers having a fiber thickness of 5 to 30 μm and a fiber length of 5 to 200 mm are suitable.

If the fiber thickness and fiber length of the glass fibers are smaller than the above values, the rigidity of the molded product obtained will decrease.

On the other hand, if the fiber thickness and fiber length are larger than the above values, shape retention will be reduced when used as a molded ceiling of an automobile.

Examples of the thermoplastic resin powder 2 include powders of polyolefin resins such as polyethylene and polypropylene, ethylene vinyl acetate copolymer resins, polystyrene resins, saturated polyester resins, and polyamide resins. A blowing agent is mixed into these thermoplastic resin powders 2. The blowing agent can be kneaded into the thermoplastic resin powder 2 by kneading the thermoplastic resin powder 2 at a temperature below the decomposition temperature of the blowing agent. For example, a low melting point polyethylene resin (melting point 105-110'C) powder is melted, a blowing agent is mixed in and kneaded, extruded into a sheet, and the sheet is crushed to form a powder. It will be done. As the blowing agent, dinitrosopentadiene, P-toluenesulfonic acid amide, etc. can be used.

In the present invention, a mat-like material 3 is formed by spraying thermoplastic resin powder 2 containing a foaming agent onto the inorganic fibers 1 described above. Thermoplastic resin powder 2 is generally 50 to 10
0 mesh is used. A known method is used to manufacture the mat-like material 3. For example, inorganic fibers 1 and thermoplastic resin powder 2 are fed to a card machine, opened,
There is a method of manufacturing the mat-like material 3 by mixing fibers and performing needle punching. Alternatively, after producing a mat-like material of the inorganic fibers 1, the thermoplastic resin powder 2 can be sprayed from above.

The amount of the thermoplastic resin powder 2 to be sprayed on the inorganic fibers 1 is 2:8 to 2:2 in the weight ratio of the inorganic fibers I to the thermoplastic resin powder 2.
It is preferable to spray in a ratio of 5:5, and the total basis weight of the mat-like material 3 is 300 to 800 g/r+(
A range of is preferred. If the amount of U[1 is too large, it becomes difficult to form into a matte shape. On the other hand, if the amount of thermoplastic resin powder 2 is too large, the resulting molded product will have a hard G
11 (Since there is less woven material, the porosity of the molded product decreases and the sound absorption properties decrease.)

In the present invention, first, the mat-like material 3 shown in FIG. 1 is heated by the heating device 4 from both sides of the mantle-like material 3, as shown in FIG. As the heating method, a known method may be used, such as a hot air heating method, a radiant heating method using an infrared heater or a far-infrared heater, or a contact heating method using an iron plate heater. By heating the cloak-like object 3 from both sides, the thermoplastic resin sprinkled on the inorganic fibers 1 melts, acts as a binder, and partially bonds with the inorganic fibers 1. Furthermore, when the mantle-like article 3 is heated and reaches the decomposition temperature of the foaming agent, the foaming agent foams. As a result, the inorganic fibers 1 bonded to the molten thermoplastic resin spread in the thickness direction, and a foamed sheet 1-5 having uniform rigidity is formed. The expansion ratio is preferably within the range of 2 to 10 times.

Next, the obtained foamed sheet 5 is subjected to compression molding using a cold press mold 6 as shown in FIG.

The thus obtained molded product is an automobile interior material 7 that is lightweight, bulky, and has excellent rigidity, as well as excellent mechanical strength.

In addition, when used as automotive ceiling materials, woven fabrics, non-woven fabrics, vinyl chloride leather, etc., in which polyethylene foam, polypropylene foam, polyvinyl chloride foam, polyurekne foam, etc. are laminated during compression molding, can be used as ceiling materials for automobiles. If the skin material 8 is laminated and molded, it can be bonded to the skin material 8 at the same time as the molding.

[Example 1] Glass fiber (thickness 7-14 μm, fiber length 50-100 μm)
mm) and 60% by weight of polyethylene resin powder containing a foaming agent was sprinkled on 40% by weight to give a thickness of 10mm and a weight of 5mm.
A matte material of 00 g/nf was formed. Both sides of this cloak-like object are heated with an infrared heater until the surface temperature reaches 180"C, melting the polyethylene resin and firmly bonding it to the glass fibers, and foaming the foaming agent to a thickness of 1.
A 5 mm molten foam sheet was formed.

This foamed sheet was placed in a mold at 30°C and compression molded for 1 minute at a pressure of 1 kg/cJ to fix the shape.

The thickness of the molded article was approximately 8 mm.

〔Effect of the invention] The present invention has the following effects.

(1) Thermoplastic resin powder containing a foaming agent is sprinkled on inorganic fibers to form a mat-like material, and both sides of the mat-like material are heated to melt the thermoplastic resin powder and form the inorganic fibers. The thermoplastic resin powder is partially strongly bonded, and the foaming agent contained in the thermoplastic resin powder is foamed, making it possible to manufacture an automobile interior material that is bulky, lightweight, and has excellent mechanical strength.

(2) Since it is molded into the desired shape by cold pressing, it is possible to bond it with the skin material at the same time as molding, simplifying the process, and it is extremely productive and does not require any special effort. Costs and equipment costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of the mat-like material used in the present invention, FIG. 2 is a diagram showing the heating process of the cloak-like material, and FIG.
The figure shows the state of molding in cold press. DESCRIPTION OF SYMBOLS 1... Inorganic fiber, 2... Thermoplastic resin powder, 3... Mat-like material, 4... Heating device, 5... Foaming sheet, 6... Cold press mold, 7... - Automotive interior materials, 8...Skin materials.

Claims (1)

[Claims] A thermoplastic resin powder containing a foaming agent is sprinkled on inorganic fibers to form a mat-like material, and the mat-like material is heated to melt and foam the thermoplastic resin powder to form a foamed sheet. A manufacturing method for automobile interior materials in which a foam sheet is formed into a desired shape by cold pressing.